One popular form of laundry detergent is the heavy duty laundry liquid. Its popularity is due in part to the convenience of the product form, in particular the ability to apply the detergent readily to soiled areas of the clothes. The popularity of laundry liquids has created a need for more convenient containers for dispensing these products. Thus, bottles having measuring cups serving as closures, and fitments incorporating drainage mechanisms and pouring spouts have appeared on the market.
One type of container is exemplified by that of Barker U.S. Pat. No. 4,550,862 wherein a bottle includes a fitment having a spout and a structure permitting the product to drain back into the container. The fitment has internal threads at its upper aspects which mate with external threads surrounding the mouth of a bottle closure. The threads at the mouth of the closure mate with their counterparts at the upper aspects of the fitment, the cup does not extend very far into the fitment, and the drainback region of the fitment can be shallow. Other containers have been developed using a different approach. The container disclosed in Davidson et al. U.S. Pat. No. 5,108,009 comprises a spout- and drainback- including fitment which snaps into the mouth of the bottle. The closure has internal threads situated within a flange which surrounds the measuring cup portion of the closure. The internal threads of the closure mate with external threads surrounding the neck opening.
While consumers appreciate the benefits of modern liquid detergent containers having measuring closures and drainback fitments, these sophisticated packages are not without their cost. Many of these containers include three separate parts, a body, a fitment and a closure. These components are typically made of plastic and each requires a certain amount of plastic to perform its structural function.
The amount of plastic material used in making liquid detergent containers, also should be considered from an environmental standpoint. It would be desirable to minimize the amount of such materials so that in those cases where the package is not recycled a smaller amount of plastic material reaches the landfill or other disposal area. Also it is desirable to develop a structure which can utilize a significant amount of recycled material. However, while decreasing the amount of plastic used is desirable, it is still necessary that the type and amount of plastic used be efficacious for its intended role in the container.
Plysu of Great Britain sells and illustrates in a brochure ultra light weight bottles under the name Paklite. Its 5 liter bottle weights 90 grams (0.53 g per fluid oz.). The bottles have a handle, eight panels, include vertical grooves extending most of the height of the panel at eight corners and have waffles in the bottom. Plysu also holds British registered design 2033440 which illustrates the bottle.
Robbins U.S. Pat. No. 4,890,757 discloses an enclosure having self supporting side walls formed of a plurality of spaced ribs with non self supporting thin webs therebetween.
Chochran U.S. Pat. No. 4,949,806 discloses a thin wall blow molded plastic container including a body, a neck support member 20 and lateral support members 18.
NL 9201806 discloses a bottle having a handle, a reinforcing profiled bottom, and a reinforcing groove (14).
GB 2164914 is directed to a bottle provided with a handle and a bottom having waffle-like grooves.
German Gebrauchsmuster 9212023 is directed to a thin walled bottle having an octagonal shape, a handle and grooves.
DE 36 39 083 discloses a bottle having a handle and provided with various reinforcing grooves.
German Gebrauchsmuster 29503460 discloses a bottle having grooves running around the top, body and bottom of the bottle.
EP 624 137 is directed to a thin walled bottle having side walls textured to 0.05 to 0.15 mm. U.S. Pat. No. 5,522,519 appears to be an equivalent. A surrounding jacket of polyethylene, polypropylene or polyethylene terephthalate may be used.
GB 2 042 408 discloses a bottle of saturated polyester resin having an opaque and matt surface.
EP 322 656 is directed to a bottle having reinforcing vertically extending ribs (76).
EP 198 587 is directed to a bottle having various reinforcing grooves.
Kalkanis U.S. Pat. No. 5,469,984 discloses a thermoplastic container having an anti-bulging base with a flat ring-shaped section and a central dome-shaped section.
It is known to adhere a bottle label to the bottle in the mold.
Jabarin U.S. Pat. No. 4,567,069 discloses blow molded polymeric containers said to have good physical properties and good resistance to environmental stress cracking. The walls and bottom of the container are fabricated from a multilayer polymeric material. A thin inner wall is fabricated from a linear low density ethylene polymer. The thicker outer wall is fabricated from a linear high density ethylene polymer. The material will generally contain two layers, but for special applications three or more may be used. The linear high density ethylene polymers will have a density of at least about 0.94 gm/ml, preferably at least 0.95 and more especially at least about 0.96 as containers prepared from such resins are said to have greater stiffness. It is said that somewhat thinner containers can be employed with no loss of stiffness.
Go et al. U.S. Pat. No. 4,577,768 is directed to polymer blends containing 75-90 wt. % linear high density ethylene polymer and 10-25 wt % of a linear low density ethylene polymer (density less than 0.93 g/ml). The blends are said to have a combination of physical properties and environmental stress crack resistance which make them well suited for conversion to blow molded containers for use in packaging aqueous detergent compositions.
Strassheimer U.S. Pat. No. 4,785,948 illustrates a container with a hexagonal section. The patent is directed to bottles with thickened portions extending completely circumferentially around the periphery.
Yoshino U.S. Pat. No. 5,080,244 discloses a synthetic resin thin walled bottle having ribs at least at its bottom portion.
Jakobsen U.S. Pat. No. 4,359,165 discloses a reinforced thermoplastic container having internal reinforcing ribs.
Yoshino U.S. Pat. No. 4,620,639 discloses synthetic resin, thin walled bottles having ribs at least at the bottom. Ribs extending the full axial length of the barrel portion, whereby buckling strength is said greatly to be increased, are disclosed in FIG. 6.
Evers U.S. Pat. No. 3,029,963 discloses a bottle with vertically extending ribs.
LaFleur U.S. Pat. No. 5,224,623 discloses a fast food container reinforced by ribs which wrap around the container side walls.
Mumpower et al. U.S. Pat. No. 5,374,459 discloses a thermoplastic laminate for long term storage of food products. It includes a core layer of EVA, two interior adhesive layers and two surface layers comprising a blend of linear ethylene alpha olefin copolymer and an ethylene unsaturated ester copolymer. Linear ethylene alpha olefin copolymer is defined to include metallocene catalyzed polymers such as those supplied by Exxon.
Exxon Chemical""s brochure entitled xe2x80x9cEXACT(trademark) PLASTOMERS for Targeted Performance in Polyolefin Modificationxe2x80x9d provides information on the properties of its metallocene polyethylene plastomers.
Stehling et al. U.S. Pat. No. 5,382,636 is directed to interpolymer blends which may comprise linear polyethylenes prepared by catalyst systems of the metallocene type. It is said that the blends of the invention can be used to advantage in all forming operations, such as blow molding, injection molding and roto molding and that molded articles include single and multilayered constructions in the form of bottles, tanks, etc.
Hodgson et al. U.S. Pat. No. 5,376,439 discloses a polymer composition comprising a blend of a very low density ethylene polymer and a low to medium density ethylene polymer. Metallocene catalysts may be used. The invention also provides for films prepared from the blend which may have a single layer construction or a laminated ABA construction wherein the A layer comprises the blend of the invention and the B or core layer comprises a different olefin layer such as high density polyethylene.
Metha et al. U.S. Pat. No. 5,358,792 is directed to heat sealable compositions comprising a) a low melting polymer comprising an ethylene based copolymer having a density of from 0.88 g/cm3 to about 0.915 g/cm3 and b) a propylene based polymer. The ethylene based copolymer is produced with a metallocene catalyst.
Hodgson U.S. Pat. No. 5,206,075 is directed to a laminar polyolefin film material having a base film layer which is a blend of an olefin polymer and a very low density copolymer of ethylene. The VLDPEs which may be used as the copolymer component of the base or sealing layers of the film of the invention can be polymerized with the use of metallocene catalyst systems. The films are said to be very useful for high speed packaging operations.
Wu U.S. Pat. No. 5,422,172 discloses an elastic laminated sheet made of a nonwoven fibrous web and an elastomeric film. The elastomeric film may be made using metallocene catalysts.
Cheruvu et al. U.S. Pat. No. 5,420,220 discloses a film of a linear low density copolymer of ethylene (LLDPE) said to have excellent processability, optical properties and impact strength. The resins are said to exhibit narrower molecular weight distribution.
Lever Brothers Company currently sells a heavy duty liquid detegent in a bottle having 25% homopolymer resin.
Chevron HiD 9602 resin is reported to have a density of 0.963, a melt index of 0.4 and to have as its property, xe2x80x9cstrength.xe2x80x9d
The following patents relate to metallocenes:
Wood et al. U.S. Pat. No. 5,419,795, Georgelos et al. U.S. Pat. No. 5,397,640, Georgelos U.S. Pat. No. 5,397,613, Quantrille et al. U.S. Pat. No. 5,393,599, Agur et al. U.S. Pat. No. 5,128,091, Petropoulos et al. U.S. Pat. No. 5,021,109, Kioka et al. U.S. Pat. No. 4,874,734, Sypula et al. U.S. Pat. No. 4,747,992 and Rim et al. U.S. Pat. No. 4,668,834.
Other containers are illustrated in Rogler et al. U.S. Pat. No. Des. 353,541, Ring U.S. Pat. No. Des. 351,347, Ring U.S. Pat. No. Des. 348,612, Darr et al. U.S. Pat. No. Des. 332,747, Jacobs U.S. Pat. No. Des. 300,005, Visser U.S. Pat. No. Des. 272,318, Platte U.S. Pat. No. Des. 265,797, Kaplan U.S. Pat. No. Des. 192,886, Price U.S. Pat. No. Des 195,697, Lyons U.S. Pat. No. Des. 286,379, Gonda U.S. Pat. No. Des. 305,407, Chambers U.S. Pat. No. Des. 306,410, Davis U.S. Pat. No. Des. 311,864, Carmine U.S. Pat. No. Des. 312,964, Fiore et al. U.S. Pat. No. Des. 321,624, Beechuk et al. U.S. Pat. No. Des. 326,052, Baird et al. U.S. Pat. No. 4,846,359, Krall et al. U.S. Pat. No. 5,232,107, Mallin U.S. Pat. No. 3,385,466 and WO 94/25350.
The present invention is directed to improved bottles for dispensing liquid household products such as liquid detergents and liquid fabric softeners. In a first embodiment, the package is comprised of a multilayer body in which the inner layer includes polyethylene made with a metallocene catalyst. Metallocene catalysts are used to produce polymers having very low densities. The bottles of the invention enjoy improved stress crack resistance yet may be lighter than traditional bottles. Preferably the metallocene polyethylene layer is the inside layer of a trilayer structure.
The metallocene layer may comprise 100% of the bottle""s inside layer. Or, the inside layer may be a blend comprising 10-99 wt % metallocene plastomer. Preferably the other blend component is high density polyethyene. The plastomer blends readily with HDPE.
The metallocene plastomer resin used in the bottle of the invention has a density of 0.910 or less, preferably 0.900 or less.
In a further embodiment, the package is comprised of a multilayer body in which the inner layer is an ESCR (environmental stress crack resistant) layer and the outer layers have elevated amounts of high density polyethylene homopolymer. The outer layers comprise at least 40 wt %, preferably 60 wt %, and especially 70 wt % and above HDPE homopolymer, excluding any added colorant. The bottles of the invention include at least three layers and may comprise four or more layers.
Among the ESCR layers which may be used as the inner layer are polymers made with metallocene catalysts, which are used to produce polymers having very low densities. Other ESCR layers which may be used include copolymers, eg, HDPE copolymers.
In a still further embodiment, the invention is directed to a bottle comprising a downwardly extending body fabricated from at least four layers and having an inner ESCR layer and an outer ESCR layer, the layers other than the inner layer including at least 40 wt %, preferably at least 50 wt %, especially at least 60 or 70 wt %, based on the total bottle body weight, high density polyethylene homopolymer. It has been discovered that in this embodiment, increased protection against stress cracking is provided while, at the same time, providing good compressive strength.
In further embodiments, the multilayer bottle body is combined with other features such as a downwardly extending body having from 6-10 axially extending side panels fabricated from the multiple polymer layers. The packages preferably are in the form of a bottle having a drainback fitment. Advantageously, the bottle is lightweight, thereby conserving valuable resources and minimizing waste, but at the same time is functional as a heavy duty liquid detergent or other dispenser. With use of the metallocene resins in accordance with the invention, the bottle may be significantly lightweighted without adversely affecting stress crack resistance (ESCR) or impact resistance properties.
Metallocene polymers are described in Stehling et al. U.S. Pat. No. 5,382,636 and Mehta et al. U.S. Pat. No. Pat. No. 5,358,792, the disclosures of which are incorporated by reference herein.
In preferred embodiments, the octagonal or other polygonal shape and multilayer resin structure, are combined with other features to form a lightweight bottle suitable for use as a heavy duty liquid detergent container. Preferably, the bottle is also suitable for other uses, such as containing liquid fabric softeners, light duty liquid detergents, eg hand dishwashing detergents, automatic dishwashing detergents such as gels, chemicals, foods, etc. Among these other, optional, features are grooves or ribs on at least 50% of the corners where the side panels intersect, an in-mold label, an increased finish diameter ranging from about 50 to about 88 mm, especially from 56 to 77 mm, and an off centered neck. The pour spout preferably has a bottom wall with a product drainage aperture. The grooves or ribs, if present, preferably extend axially at least 60% of the distance along the intersections of the panels. An optional tapered base panel extends from the side panels to the bottle base.
Pouring of product from the container is believed to be faciliated in the present combination of light weight and off-centered neck.
The lighter weight of the body of the bottle and the finish make the bottle less expensive and more sparing of valuable resources. Moreover, less plastic material needs to be recycled or disposed of in the landfill or otherwise. Bottles according to the invention preferably weigh approximately 20-50% less than bottles traditionally used to contain heavy duty liquids. Preferably the bottle of the invention (not include the closure or fitment) weighs less than 1.2 grams per fluid oz of capacity. Especially preferred is that the bottle weigh between 6 gram and 0.5 grams per fluid oz.
The bottles of the various embodiments of the invention may also include an optional handle or other integral gripping feature.
As indicated above, the multilayer bottle of the invention is advantageously fabricated with certain resins. In addition to the inner metallocene polyethylene, layer, a bottle having one or more of the following is preferred: an outer layer comprised of a high density resin and a layer, preferably a middle layer, employing at least 25% recycled resin.
For a more complete understanding of the above and other features and advantages of the invention, reference should be made to the following detailed description of preferred embodiments and to the accompanying drawings.